1. Field of the Invention
The present invention relates to a vacuum cleaner. More particularly, the present invention relates to a multi-cyclone dust separating apparatus employed in a vacuum cleaner to centrifuge dirty substances drawn into the vacuum cleaner by two stages.
2. Description of the Related Art
Generally, a vacuum cleaner includes a bottom brush drawing dust-laden air from a surface being cleaned, a motor driving chamber having a vacuum generator, and a vacuum cleaner body having a cyclone dust separating apparatus.
A cyclone dust separating apparatus is constructed such that it separates and collects dust by generating a whirling current from the air being drawn from the bottom brush, and discharges clean air to the motor driving chamber. Recently introduced multi-cyclone dust separating apparatus aims to increase dust collecting efficiency, by employing first and second cyclones to filter dust from the air by at least two stages, and in this construction, one or more second cyclones are usually employed.
Related art can be found in WO02/067755 and WO02/067756 to Dyson Ltd. In these examples, upstream cyclone as the first cyclone and downstream cyclone as the second cyclone are arranged in a vertical manner, and thus usually employed in upright type vacuum cleaners, but hardly applicable in canister type cleaners.
The same applicant has disclosed a multi-cyclone dust separating apparatus in Korean Patent Application 2003-62520 in which the first cyclone is nested in the second cyclone to decrease overall height of the cyclones. However, the applicant has now noted that demand still remains for more compact-sized vacuum cleaners, especially for home use.
Another need was found in the fact that the cyclone dust separating apparatuses are usually in fixed size and thus compacter vacuum cleaner has lower dust collecting capacity. Because the cleaners with lower dust collecting capacity are filled with dust sooner than others, it needs be replaced frequently. Therefore, a way to improve dust collecting capacity of cyclones of fixed size, is necessary.